Drilling control mechanism



May 10, 1938. w. BRAUER 2,117,078

DRILLING CONTROL MECHANI SM gmc/Mw" WALTER BRAUER May 10, 1938. w.BRAUER 2,117,078

DRILLING. CONTROL MEGHAISM Filed Jan. 9, 1937 v 2 Sheets-Shet 2 P' 2. iH

WALTER RAUER.

mmm.

Patented May 10, 1938 UNITED STATES PATENT IA-'FICE 6 Claims.

The invention relates to a brake control mechanism where the brakegoverns the movement of a drum carrying a cable. f

In many instances and particularly in well drilling operations the drillbit is advanced due to its own weight while it is being suspended by a.block and tackle froma drum. A brake mechanism applied to the drum isusually controlled so as to pay out the cable as the drilling operationprogresses. It is needless to say that if the cable is released tooslowly the drilling operation will be slowed down, while on the otherhan l, if the cable is paid out too fast then too much weight will bepermitted to rest upon the drill bit which causes unnecessary deflectionof the' drill bit from the vertical. It is desirable, therefore, to payout the cable so as to feed the drill bit in proportion to the weight orthe strain on the cable due to the weight of the bit. The rate at whichthe drill bit penetrates the formation of course varies with theformation being encountered and the present mechanism has therefore beendevised with a view of controlling the brake mechanism as a function ofthe weight i5 suspended by the cable so that the mechanism will operateautomatically to maintain a substantially uniform weight on the cablewhich is suspending the drilling equipment.

It is one of the objects of the invention to provide an automaticallyoperating mechanism for brakes which will function in proportion to theload on the brake.

Another object of the invention is to provide a uid pressure controlmechanism wherein there is a continuous circulation of pressure fluid.

Another object of the invention is to provide a safety mechanism forfluid pressure operated brake devices so as to apply the brake in eventthe pressure in the system drops below a predetermined value.

Another object of the invention is to provide a diiierential pressureoperated diaphragm in a drilling control mechanism so that a variablepressure due to a fluctuating load can be bal- 5 anced by a constantpressure in order to control the drilling operation.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawings, wherein: l

Fig. 1 is a side view of a derrick brake and control mechanismconstruction illustrating the various parts in section.

Fig. 2 is'a top plan view of the assembly by which the control isobtained; and illustrating the (Cl. Z55-19) fluid piping connection tothe various parts of the device.

The invention ls being described in connection with well drillingequipment, but it is to lbe understood that it may be applied to variousdevices where a brake is to be operated as a function of the load beingbraked.

All of the equipment has been illustrated as being positioned upon thederrick floor 2 inside of the confines of the derrick legs 3. 'I'hedrawworks assembly is illustrated generally at I and of course includesthe drum 5 upon which the cable is reeled in order to effect the raisingand i lowering of the drill stem which is shown at G asprojectingthrough the rotary table 1. It is of course understood that the rotarytable is rotated by means of the pinion shaft and the sprocket 9, whichis in turn driven by a chain from the sprocket i i of the drawworks l.The cable which supports the string of pipe and the drill bit in thewell bore passes upwardly over the crown block in the top of the derrickand of course through the usual traveling block and thence down to thedrum 5 of the drawworks.

The other end of the cable known as the dead line is seen at i4 in Fig.1 and will be anchored l at i6 to the derrick floor.

In order to control the rotation of drum 5 the brake bands Il areapplied to each end of tne drum and will be operated by the brake leveriB seen in both Figs. l and 2.

During the drilling operation the brake lever i8 will be manipulated toallow the weight of the drill bit and the drill .stem to unreel thecable from the drum 5, the brake being applied to retard the paying outof the cable so that an excessive amount of weight will not be appliedto the drill bit, and to controlthe adjustment of the bit in accordancewith the formation being encountered, the `rate of rotation of the bit,and various other circumstances which have a bearing upon the rate ofdrilling.

'I'he present invention islin the nature of an improvement over my priorPatent 1,779,656, granted October 28, 1930, wherein the general`combination of an automatic brake regulator for rotary drilling is.disclosed. The present improvement consists primarily in` providingsuitable control mechanism for the fluid pressure so as to equalize theaction of the parts and to avoid sharp fluctuations in the fluidpressure used to control the mechanism, as well as to apply circulatingfluid pressure which can be more accurately controlled than thearrangement of the fluid pressure shown in my prior patent.

In order to provide a source of circulating fluid pressure a supply tank20 has been shown in Fig. 2. Disposed in this tank is circulating pump2| which may be operated by the drive wheel 22 from a connection 23 onthe end of the rotary drive pinion shaft. While this arrangement hasbeen shown, it is to be understood that the power for circulating thefluid pressure liquid 24 from the tank 20 may be provided from anysuitable source. The pump 2| discharges into the pipe line 21 whichpasses into the control device 28 which is shown in section in Fig. 1.The pressure in this fluid circuit is maintained constant by the use ofa suitable pressure control valve 25 which may as a practical mattercomprise a suitable by-pass valve. In such event it is obvious that thevolume of liquid pumped by circulating pump 2| will be sufcient to llcontrol chamber 66 at such rate that the desired change in braking willoccur. The fluid from this pipe line 21 discharges into a chamber 30 inthe housing 3| and beneath a diaphragm 32. 'Ihis pressure of coursetends to raise the diaphragm 32 away some so as to move it out ofcontact with a seat 33 which is formed on a nipple 34 carried by thebase 35 of the control mechanism. The diaphragm 32 normally closes thenipple 34 of the valve 33 so that there can be no flow of fluid from thechamber 30 into the outlet pipe 31 which is connected to the nipple 34.The movement of the diaphragm 32 is assisted by a spring 40 which bearsagainst the partition 4| of the housing- 3|, this spring beingadjustable by means of hand wheel 42, which is threaded on the stem 43,which is connected to the diaphragm 32. In other words, the diaphragm isloaded by the spring 40 in any desired amount of adjusting the handwheel 42. The pressure through the line 21 and in the chamber 30 willassist the loading of spring 40 before the diaphragm 32 can moveupwardly.

In order to control the movement of the diaphragm as a function of theload on the drilling cable a iluid pressure connection 45 leads into thechamber 46 in the housing 3| above the diaphragm 32 and this connection45 leads to a cylinder 41 which carries a piston 48 which pressesagainst the dead line I4 of the cable. A suitable roller 49 is connectedto the piston 48. The cylinder 41 is carried by a bracket 5l) which isshown as clamped to the dead line so that a variable pressure on thecable will impart a variable pressure to the piston 48 so that the fluidpressure in the chamber 5| will reflect this variable pressure in thechamber 46 of the control mechanism.

It will be apparent that the diaphragm 32 is thus controlled by adifferential pressure so that it is either balanced or unbalanced,depending upon the variable pressure in the chamber 46, it beingunderstood that the spring 40 will be used to load the diaphragm,depending upon the number of times the cable is reeved through thetraveling block and the crown block and upon the weight of the drillstern in the hole.

The operation of the brake lever I8 is effected by means of the linkconnection 62 which is in turn connected to the stem 63 which carries apist0n 64 disposed in the pressure cylinder 65. It will be observed thatthe uid pressure from the outlet pipe 31 is directed into the pressurechamber 66 so that it tends to move the piston 64 down, wardly and inthis manner apply the brake to the brake drlmi. This fluid pressure isadmitted to the chamber 66 only when the constant pressure in thechamber 30 exceeds the variable pressure in the chamber 46.

It has been found in practice, however, that a constant pressure issubject to variation due to expansion and contraction of the piping andother equipment due to leakage and to various other circumstances whichcannot bey accurately controlled; for this reason the circulatingmechanism described above has been provided so that there is a constantpressure applied in the chamber 30 which is admitted periodically to thechamber 6C. In order to effect a complete circulation of the liquid theoutlet 10 has been provided on the cylinder 65 and a suitable choke 1|is disposed in this discharge outlet 10. The handle 12 serves to adjustthe choke so as to restrict or enlarge the volume of flow through thechamber 66. The outlet pipe 13 continues as seen in Fig. 2 anddischarges into the supply tank 20.

It is thus apparent that choke 1| permits adjustment of the rate of flowof fluid from control chamber 66 such that when an increased braking isdesired the rate of ow of fluid through valve 33 to control chamber 66exceeds a discharge flow through choke 1|, and brake lever I8 is moveddownwardly by piston 64. On the other hand, if a decrease in braking isdesired the rate of ow of fluid from control chamber 66 exceeds thatfrom valve 33 into the chamber whereby piston 64 will rise and brakingwill be decreased.

The safety feature has been provided in event there is breakage in anyof the piping or a failure of the supply pump 2| by an arrangement of apipe which is connected to the supply pipe 21 and carries a pressuregaugev 8|. This pipe leads to a diaphragm 82 which is carried by acylinder 83 on the safety housing 84. A latch member 85 is connected tothe diaphragm 82 and is normally pressed inwardly due to fluid pressurethrough the pipe 80 on the diaphragm 82. A spring 86 resists apredetermined amount of pressure applied to the diaphragm so that whilethe latch 85 normally remains in the position shown in Fig. 1, if thepressure drops below this predetermined amount then thel spring 96 willmove the latch 85 to the left or to retracted position.

The latch 85 normally serves to support a plate 88 which is'connected bya chain 90 to the brake arm I8. A spring 9| normally urges the plate 88downwardly to retain it against the latch 85. When the latch 85 isremoved due to a reduction in pressure the spring 9| will exert adownward pull on the stem at 89 and of course on the brake arm I8 so asto set the brake. This prevents unnecessary and undesirable relation ofthe cable with the brake mechanism in event of difficulty with any ofthe control mechanism.

Broadly, the invention contemplates a control mechanism for brakes whichwill be uniform in its action and which will be operated as a functionof the load being braked. j

What is claimed is:

1. A brake control for feeding the cable of a drilling rig comprising incombination with the brake of a liquid pressure mechanism to exert apull thereon, means to transmit liquid pressure to said mechanism as afunction of the force opposing said brake, and means to discharge theVliquid from said mechanism at a predetermined rate so as to dampthefluctuation of the pressure actuating said mechanism.

2. A brake control for feeding the cable of a drilling rig comprising incombination with the brake of a liquid pressure Amechanism to exert apull thereon, means totransmit liquid pressure to said mechanism as afunction of the force opposing said brake, means to discharge the liquidfrom said mechanism at a predetermined rate so as to damp theiluctuation of the pressure actuating said mechanism, and additionalmeans to set said brake ln event of reduction of the operating liquidpressure below a predetermined value.

3. A control mechanism for drilling rig brakes where the rate of feedingthe cable from the brake drum is dependent upon the load being carriedwhich comprises the combination of a supply of liquid subject to apressure which is a function of the load on the cable, a diaphragmsubjected to such pressure, means to apply a constant pressure to saiddiaphragm in balancing the load pressure, `a valve operated by saiddiaphragm to release the constant pressure when the load pressure isoverbalanced, and means to actuate said brake when the ow of pressureiiuid 'released by said valve exceeds a predetermined volume.

4. A control mechanism for drilling rig brakes where the rate of feedingthe cable from the 'brake drum is dependent upon the load being carriedwhich comprlsesthe combination of a supply of liquid subject to apressure which is a function of the load on the cable, a diaphragmsubjected to such pressure, means to apply a constant pressure to saiddiaphragm in balancing the load pressure, al valve operated by saiddiaphragm to release the constant pressure when the load pressure isoverba'lanced, means to actuate said brake when the flow of pressurefluid released by said valve exceeds a predetermined volume, said lastmeans including a choke.

5. A control mechanism for drilling rig brakes Where the rate of feedingthe cable from the brake drum is dependent upon the load being carriedwhich comprises the combination of a supply of liquid subject to apressure which is a function of the load on the cable, a diaphragmsubjected to such pressure. means to apply a constant pressure to saiddiaphragm in balancing the load pressure, a valve operated by saiddiaphragm 4to release the constant pressure when the load pressure isover-balanced, means to actuate said brake when the iiow of pressure uidreleased by said valve exceeds a predetermined volume, said last meansincluding a choke, and additional means to actuate said brake if theconstant pressure falls below a predetermined value.

- 6. In an automatically operable fluid pressure brake control mechanisma safety device to actuate the brake in event the operating pressurefalls below a predetermined value including a mechanically operatedmember to apply the brake, and `fluid pressure latching means to releasesaid member when the pressure falls below a predetermined value. y A

WALTER BRAUER.

